code: def post_generation_process(self, output):
      sentences = output["sentences"]
      modified = []
      for sentence in sentences:
          sentence = "answer:" + sentence.split(" \nanswer:")[1]
          modified.append(sentence)
      output["sentences"] = modified
      return output
  
imports: import json
  import pickle
  from typing import List, Tuple
  import numpy
  import torch
  import torch.distributed
  from nemo.collections.nlp.modules.common.lm_utils import pad_batch
  from nemo.collections.nlp.modules.common.megatron.retrieval_services.retrieval_service import ComboRetrievalService
  from nemo.collections.nlp.modules.common.text_generation_strategy import TextGenerationStrategy
label_desc: Use image node_id 4 for calling the RetroQAModelTextGenerationStrategy obj's underlying member method code with example usage: obj.post_generation_process(output) and returns: output